This invention relates to a method for the inhibition of neoplastic cells, for example, for the treatment or prevention of precancerous lesions or other neoplasias in mammals.
Each year in the United States alone, untold numbers of people develop precancerous lesions, which is a form of neoplasia, as discussed below. Such lesions exhibit a strong tendency to develop into malignant tumors, or cancer. Such lesions include lesions of the breast (that can develop into breast cancer), lesions of the skin (that can develop into malignant melanoma or basal cell carcinoma), colonic adenomatous polyps (that can develop into colon cancer), and other such neoplasms. Compounds that prevent or induce the remission of existing precancerous or cancerous lesions or carcinomas would greatly reduce illness and death from cancer.
For example, approximately 60,000 people die from colon cancer, and over 150,000 new cases of colon cancer are diagnosed each year. For the American population as a whole, individuals have a six percent lifetime risk of developing colon cancer, making it the second most prevalent form of cancer in the country. Colon cancer is also prevalent in Western Europe. It is believed that increased dietary fat consumption is increasing the risk of colon cancer in Japan.
In addition, the incidence of colon cancer reportedly increases with age, particularly after the age of 40. Since the mean ages of populations in America and Western Europe are increasing, the prevalence of colorectal cancer should increase in the future.
To date, little progress has been made in the prevention and treatment of colorectal cancer, as reflected by the lack of change in the five-year survival rate over the last few decades. The only cure for this cancer is surgery at an extremely early stage. Unfortunately, most of these cancers are discovered too late for surgical cure. In many cases, the patient does not experience symptoms until the cancer has progressed to a malignant stage.
In view of these grim statistics, efforts in recent years have concentrated on colon cancer prevention. Colon cancer usually arises from pre-existing benign neoplastic growths known as polyps. Prevention efforts have emphasized the identification and removal of colonic polyps. Polyps are identified by x-ray and/or colonoscopy, and usually removed by devices associated with the colonoscope. The increased use of colon x-rays and colonoscopies in recent years has detected clinically significant precancerous polyps in four to six times the number of individuals per year that acquire colon cancer. During the past five years alone, an estimated 3.5 to 5.5 million people in the United States have been diagnosed with adenomatous colonic polyps, and it is estimated that many more people have or are susceptible to developing this condition, but are as yet undiagnosed. In fact, there are estimates that 10-12 percent of people over the age of 40 will form clinically significant adenomatous polyps.
Removal of polyps has been accomplished either with surgery or fiber-optic endoscopic polypectomyxe2x80x94procedures that are uncomfortable, costly (the cost of a single polypectomy ranges between $1,000 and $1,500 for endoscopic treatment and more for surgery), and involve a small but significant risk of colon perforation which can be fatal. Overall, about $2.5 billion is spent annually in the United States in colon cancer treatment and prevention.
In the breast, breast cancer is often treated surgically, often by radical mastectomy with its painful and emotional aftermath. Such surgery is costly, too.
As indicated above, each lesion carries with it a chance that it will develop into a cancer. The likelihood of cancer is diminished if a precancerous lesion is removed. However, many of these patients demonstrate a propensity for developing additional lesions in the future. They must, therefore, be monitored periodically for the rest of their lives for reoccurrence.
In most cases (i.e. the cases of sporadic lesion formation, e.g. so-called common sporadic polyps), lesion removal will be effective to reduce the risk of cancer. In a small percentage of cases (i.e. cases where numerous lesions form, e.g. the so-called polyposis syndromes), removal of all or part of the effected area (e.g. the colon) is indicated. For example, the difference between common sporadic polyps and polyposis syndromes is dramatic. Common sporadic polyp cases are characterized by relatively few polyps that can usually be removed leaving the colon intact. By contrast, polyposis syndrome cases can be characterized by many (e.g. hundreds or more) of polypsxe2x80x94literally covering the colon in some casesxe2x80x94making safe removal of the polyps impossible short of surgical removal of the colon.
Because each lesion carries with it a palpable risk of cancerous development, patients who form many lesions (e.g. polyposis syndrome patients) invariably develop cancer if left untreated. Surgical removal of the colon is the conventional treatment in polyposis patients. Many polyposis patients have undergone. a severe change in lifestyle as a result of the disfiguring surgery. Patients have strict dietary restrictions, and many must wear ostomy appliances to collect their intestinal wastes.
The search for drugs useful for treating and preventing cancer is intensive. Indeed, much of the focus of cancer research today is on the prevention of cancer because chemotherapy for cancer itself is often not effective and has severe side effects. Cancer chemoprevention is important for recovered cancer patients who retain a risk of cancer reoccurrence. Also, cancer prevention is important for people who have not yet had cancer, but have hereditary factors that place them at risk of developing cancer. With the development of new genetic screening technologies, it is easier to identify those patients with high-risk genetic factors, such as the potential for polyposis syndrome, who would greatly benefit from chemopreventative drugs. Therefore, finding such anti-cancer drugs that can be used for prolonged preventive use is of vital interest.
Known chemopreventative and chemotherapeutic drugs are believed to kill cancer cells by inducing apoptosis, or as sometimes referred to as xe2x80x9cprogrammed cell death.xe2x80x9d Apoptosis naturally occurs in virtually all tissues of the body, and especially in self-renewing tissues such as bone marrow, gut, liver and skin. Apoptosis plays a critical role in tissue homeostasis, that is, it ensures that the number of new cells produced are correspondingly offset by an equal number of cells that die. For example, the cells in the intestinal lining divide so rapidly that the body must eliminate cells after only three days in order to prevent the overgrowth of the intestinal lining.
Recently, scientists have realized that abnormalities of apoptosis can lead to the formation of precancerous lesions and carcinomas. Also, recent research indicates that defects in apoptosis play a major role in other diseases in addition to cancer. Consequently, compounds that modulate apoptosis could be used to prevent or control cancer, as well as used in the treatment of other diseases.
Unfortunately, even though known chemotherapeutic drugs may exhibit such desirable apoptosis effects, most chemotherapeutic drugs have serious side effects that prohibit their long-term use, or use in otherwise healthy individuals with precancerous lesions. These side effects, which are a result of nonspecific cytotoxicity of the drugs, include hair loss, weight loss, vomiting, immune suppression and other toxicities. For this reason, there is a need to identify new drug candidates for therapy of patients with precancerous lesions that do not have such serious side effects in humans.
In recent years, several nonsteroidal anti-inflammatory drugs (xe2x80x9cNSAIDsxe2x80x9d), originally developed to treat arthritis, have shown effectiveness in inhibiting and eliminating colonic polyps. Polyps virtually disappear when the patients take such drugs, particularly when the NSAID sulindac is administered. However, the prophylactic use of currently available NSAIDs, even in polyposis syndrome patients, is marked by severe side reactions that include gastrointestinal irritations and ulcerations. Once NSAID treatment is terminated due to such complications, the polyps return, particularly in polyposis syndrome patients.
Sulindac has been particularly well received among the NSAIDs for the polyp treatment. Sulindac is a sulfoxide compound that itself is believed to be inactive as an anti-arthritic agent. The sulfoxide is reportedly converted by liver enzymes to the corresponding sulfide, which is acknowledged to be the active moiety as a prostaglandin synthesis inhibitor. The sulfide, however, is associated with the side effects of conventional NSAIDs. The sulfoxide is also known to be metabolized to sulfone compound that has been found to be inactive as an inhibitor of prostaglandin synthesis but active as an inhibitor of precancerous lesions.
This invention includes a method of inhibiting neoplastic cells by exposing those cells to a pharmacologically effective amount of those compounds described below. Such compounds are effective in modulating apoptosis and eliminating and inhibiting the growth of neoplasias such as precancerous lesions.
The compounds of that are useful in the methods of this invention include those of Formula I: 
wherein R1 and R2 are independently selected from the group consisting of hydrogen, A, OA, alkenyl, alkynyl, xe2x80x94NO2, xe2x80x94CF3 or halogen, with the proviso that one of R1 or R2 is not hydrogen; or R1 and R2 together form a C3-5 alkylene group;
R3 and R4 are independently selected from the group consisting of hydrogen, A, xe2x80x94OA, halogen, xe2x80x94NO2, xe2x80x94NH2, xe2x80x94NHA or xe2x80x94NAAxe2x80x2, or R3 and R4 are together form a moiety selected from the group consisting of xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94 or xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94O,
X is selected from the group consisting of an unsubstituted or a substituted 5-7 membered saturated or unsaturated heterocyclic ring, wherein the ring is selected from the group consisting of phenyl, cyclopentyl, cyclohexyl, cycloheptyl, furyl, dioxolanyl, thienyl, pyrrolyl, pyrrolidinyl, inidazolyl, pyrazolyl, pyridyl, piperidinyl, morpholinyl, pyranyl, dioxanyl, pyridazinyl, pyrimidinyl, piperazinyl, quinolyl, and isoquinolyl and wherein the substitutents on the xe2x80x9cXxe2x80x9d ring are one or two selected from the group consisting ofxe2x80x94lower alkyl COOH, xe2x80x94COOA, xe2x80x94CONH2, xe2x80x94CONAAxe2x80x2, xe2x80x94CONHA, xe2x80x94CN, xe2x80x94CH2COOH or xe2x80x94CH2CH2COOH;
A and Axe2x80x2 are independently selected from the group consisting of hydrogen or C1-6 alkyl; and
n is 0, 1, 2 or 3; and
physiologically acceptable salts thereof.
The present invention also is a method of treating a patient with such lesions by administering to a patient a pharmacologically effective amount of a pharmaceutical composition that includes a compound of Formula I, wherein R1 etc. are as defined above. Preferably, this composition is administered without therapeutic amounts of an NSAID.
The present invention is also a method of treating individuals with neoplastic lesions by administering a pharmacologically effective amount of an enterically coated pharmaceutical composition that includes compounds of this invention.
Also, the present invention is a method of inhibiting the growth of neoplastic cells by exposing the cells to an effective amount of compounds of Formula I, wherein R1 through R7 and Y are defined as above.
In still another form, the invention is a method of inducing apoptosis in human cells by exposing those cells to an effective amount of compounds of Formula I, wherein R1 etc. are defined as above where such cells are sensitive to these compounds.
Additionally, in yet another form, the invention is a method of treating a patient having a disease which would benefit from regulation of apoptosis by treating the patient with an effective amount of compounds of Formula I, wherein R1 etc. are defined as above. The regulation of apoptosis is believed to play an important role in diseases associated with abnormalities of cellular growth patterns such as benign prostatic hyperplasia, neurodegenerative diseases such as Parkinson""s disease, autoimmune diseases including multiple sclerosis and rheumatoid arthritis, infectious diseases such as AIDS, and other diseases, as well.
As used herein, the term xe2x80x9cprecancerous lesionxe2x80x9d includes syndromes represented by abnormal neoplastic, including dysplastic, changes of tissue. Examples include dysplasic growths in colonic, breast, bladder or lung tissues, or conditions such as dysplastic nevus syndrome, a precursor to malignant melanoma of the skin. Examples also include, in addition to dysplastic nevus syndromes, polyposis syndromes, colonic polyps, precancerous lesions of the cervix (i.e., cervical dysplasia), esophagus, prostatic dysplasia, bronchial dysplasia, breast, bladder and/or skin and related conditions (e.g., actinic keratosis), whether the lesions are clinically identifiable or not.
As used herein, the term xe2x80x9ccarcinomasxe2x80x9d refers to lesions that are cancerous. Examples include malignant melanomas, breast cancer, prostate cancer and colon cancer.
As used herein, the term xe2x80x9cneoplasmxe2x80x9d refers to both precancerous and cancerous lesions and hyperplasia.
As used herein, the term xe2x80x9chalogenxe2x80x9d means fluorine, chlorine, bromine, or iodine.
Compounds useful in the practice of this invention may be formulated into pharmaceutical compositions together with pharmaceutically acceptable carriers for oral administration in solid or liquid form, or for rectal or topical administration, although carriers for oral and parenteral administration are most preferred.
Pharmaceutically acceptable carriers for oral administration include capsules, tablets, pills, powders, troches and granules. In such solid dosage forms, the carrier can comprise at least one inert diluent such as sucrose, lactose or starch. Such carriers can also comprise, as is normal practice, additional substances other than diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets, troches and pills, the carriers may also comprise buffering agents. Carriers such as tablets, pills and granules can be prepared with enteric coatings on the surfaces of the tablets, pills or granules. Alternatively, the enterically coated compound can be pressed into a tablet, pill, or granule, and the tablet, pill or granules for administration to the patient. Preferred enteric coatings include those that dissolve or disintegrate at colonic pH such as shellac or Eudraget S.
Pharmaceutically acceptable carriers include liquid dosage forms for oral administration, e.g., pharmaceutically acceptable emulsions, solutions, suspensions, syrups and elixirs containing inert diluents commonly used in the art, such as water. Besides such inert diluents, compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, and sweetening, flavoring and perfuming agents.
Pharmaceutically acceptable carriers for topical administration include DMSO, alcohol or propylene glycol and the like that can be employed with patches or other liquid-retaining material to hold the medicament in place on the skin so that the medicament will not dry out.
Pharmaceutically acceptable carriers for rectal administration are preferably suppositories that may contain, in addition to the compounds of this invention excipients such as cocoa butter or a suppository wax, or gel.
When the present invention is used as a medicine for such diseases, it is administered by oral administration or parenteral administration. The dose thereof varies depending upon the extent of symptom; the age, sex, weight and drug sensitivity of a patient; the method, timing and interval of administration; the type of pharmaceutical preparation; the type of a medicine to be administered together therewith; the type of an active ingredient and so forth.
In general the compounds useful in the practice of this invention are administered preferably in dosages between 1 and 500 mg, in particular between 5 and 100 mg per dosage unit. The daily dosage is preferably between approximately 0.02 and 10 mg/kg body weight. The specific dosage for each patient depends on various factors, e.g., on the efficacy of the used specific compound, on the age, the body weight, general health, gender, nutrition, the application time and method, elimination velocity, the pharmaceutical combination and the gravity of the respective disease for which the treatment is meant. Oral administration is preferred.
A and Axe2x80x2 are independently preferably alkyl with 1-6 carbon atoms. In the preceding formulae xe2x80x9calkylxe2x80x9d can be linear, branched or cyclic, but preferably linear with 1-6 carbons and more preferably 1-5 carbons, most preferably methyl, ethyl or propyl. However, isopropyl, butyl, isobutyl, butyl or tert-butyl, n-pentyl, neopentyl or isopentyl can be employed.
xe2x80x9cAlkylenexe2x80x9d is preferably linear and is most preferred propylene, butylene or pentylene.
Of the substituents R1 and R2, one is preferably hydrogen, while the other is preferably propyl or butyl, most preferred is ethyl or methyl. However, R1 and R2 can also together be propylene, butylene or pentylene.
xe2x80x9cHaloxe2x80x9d or xe2x80x9chalogenxe2x80x9d preferably refer to F, Cl or Br. However iodine can also be employed.
xe2x80x9cAlkenylxe2x80x9d is preferably vinyl, 1- or 2-propenyl, 1-butenyl, isobutenyl, sec.-butenyl. However, 1-pentenyl, iso-pentenyl or 1-hexenyl can be employed.
xe2x80x9cAlkinylxe2x80x9d is preferably ethyinyl, or propyn-1-yl. However, butyn-1-, butyn-2-yl, penyn-1-, pentyn-2- or pentyn-3-yl can be employed.
The substitutents R3 and R4 can be the same or different and are preferably, in position 3 or 4 of the phenyl ring. They are for example independently hydrogen, alkyl, alkoxy, nitro, amino, alkylamino (e.g., methylamino), dialkylamino (e.g., dimethylamino), or halo. Alternatively, R3 and R4 together are ethylenoxy, methylenedioxy or ethylendioxy. R3 and R4 also can be alkoxy (e.g., methoxy, ethoxy or propoxy).
X is preferably single or double substituted phenyl, cyclopentyl, cyclohexyl, cycloheptyl, 2,3-dihydro-2-, -3-, -4- or -5-furyl, 2,5-dihydro-2-, -3-, -4- or -5-furyl, tetrahydro-2- or -3-furyl, 1,3-dioxolan-4-yl, tetrahydro-2- or -3-thienyl, 2,3-dihydro-1-, -2-, -3-, -4- or -5-pyrrolyl, 2,5-dihydro-1-, -2-, -3-, -4- or -5-pyrrolyl, 1-, 2- or 3-pyrrolidinyl, tetrahydro-1-, -2- or -4-imidazolyl, 2,3-dihydro-1-, -2-, -3-, -4- or -5-pyrazolyl, tetrahydro-1-, -3- or -4-pyrazolyl, 1,4-dihydro-1-, -2-, -3- or -4-pyridyl, 1,2,3,4-tetrahydro-1-, -2-, -3-, -4-, -5- or -6-pyridyl, 1-, 2-, 3- or -4-piperidinyl, 2-, 3- or 4-morpholinyl, tetrahydro-2-, -3-, or -4-pyranyl, 1,4-dioxanyl, 1,3-dioxan-2-, -4- or -5-yl, hexahydro-1-, -3- or -4-pyridazinyl, hexahydro-1-, -2-, -4- or -5-pyrimidinyl, 1-, 2- or 3- piperazinyl, 1,2,3,4-tetrahydro-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-quinolyl, 1,2,3,4-tetrahydro-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-isoquinolyl.
The substituent(s) on the xe2x80x9cXxe2x80x9d ring preferably are selected from the group consisting of lower alkyl, xe2x80x94COOH, xe2x80x94COOCH3, xe2x80x94COOC2H5, xe2x80x94CONH2, xe2x80x94CON(CH3)2, xe2x80x94CONHCH3, xe2x80x94CN, xe2x80x94CH2COOH or xe2x80x94CH2CH2COOH.
More preferred compounds useful in the practice of this invention are those in groups 1-5 below
In group 1, X is single or double substituted phenyl, 1-piperidinyl or cyclohexyl wherein said substitutents are selected from the group consisting of xe2x80x94COOH, xe2x80x94COOA, xe2x80x94CONH2, xe2x80x94CONAAxe2x80x2, xe2x80x94CONHA, xe2x80x94CN, xe2x80x94CH2COOH or xe2x80x94CH2CH2COOH;
In Group 2, R1 and R2 are independently selected from the group consisting of hydrogen, A, OA, NO2, CF3 or halogen, with the proviso that one of R1 and R2 is not hydrogen; R3 and R4, together form a moiety selected from the group consisting of xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94 or xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94O; X is as defined in Group 1, and n is 1.
In group 3, R1 and R2 are as defined in group 2; R3 and R4 are independently selected from the group consisting of hydrogen, A, OA, halogen, xe2x80x94NO2, xe2x80x94NH2, xe2x80x94NHA or xe2x80x94NAAxe2x80x2; X is as defined in group 1; and n is 1;
In group 4, R1 and R2 together for a C3-5 alkylene, R3 and R4 together form a moiety selected from the group consisting ofxe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94, xe2x80x94O,xe2x80x94CH2xe2x80x94Oxe2x80x94 or xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94O, X is as defined in group 1; and n is 1;
Finally, in group 5, R1, R2 together form a C3-5 alkylene; R3 and R4 are independently selected from the group consisting of hydrogen, A, OA, halogen, NO2, NH2, HHA or NAAxe2x80x2; X is as defined in group 1; and n is 1.
Processes for preparing compounds usefully in this invention are described in PCT Patent Application No. 97/05530 (which is incorporated herein by reference). Those processes are set forth below. However, those processes, as well as processes for making the starting materials are reportedly known methods described in the literature (e.g., Houben-Weyl, Methods of Organic Chemistry, Georg Thieme, Stuttgart). The same reaction conditions as those known for the respective reactions can be employed.
Specifically, compounds useful in practicing this invention can be synthesized in several general ways, depending on the types of substitutions. For example, compounds of Formula I (as well as their salts) where X is a single or double substituted saturated 5-7 membered nitrogen-containing heterocycle which is connected via the nitrogen is made using a compound of Formula II 
wherein R1, R2, R3, R4and n have the meanings above, but L is Cl, Br, OH, SCH3 or a reactive esterfied OH-group. The compound of Formula II is allowed to react with a xe2x80x9cR5 substitutedxe2x80x9d saturated 5-7 membered nitrogen-containing heterocycle (where R5 has the given designation).
Alternatively, the synthesis of compounds of Formula I (as well as their salts) where X is a substituted, unsaturated or saturated 5-7 membered isocycle which is connected a carbon atom on its ring to the theinopyrimidine ring is as follows. A compound of Formula III 
wherein R1, R2 and X have the meanings described above and L is Cl, Br, OH, SCH3 or a reactive esterified OH-group is allowed to react with a compound of Formula IV 
wherein R3, R4 and n have the given designations to obtain the desired compound.
In still another method to synthesize a compound of Formula I, one compound of Formula I can be converted to another. For example, a substituent R3, R4 and/or X can be transformed to another substituent R3, R4, and/or X, e.g., by the saponification of an ester, or by reduction of a nitro group. Also an acid compound of Formula I can be converted to one of its salts by treatment with a base.
If L is a reactive esterified OH-group, it is preferably alkylsulfonyloxy with C1-6 (preferably methylsulfonyloxy) or arylsulfonyloxy with C6-10 (preferably phenyl-or p-tolylsulfonyloxy, also 2-naphthalenesulfonyloxy).
The starting materials can also, if necessary, be made in situ, so that they are not isolated from the reaction mixture but are immediately allowed to react to compounds of Formula I. On the other hand, the reaction can also be done stepwise.
The compounds of Formula I, wherein X is connected via N to the thienopyrimidine ringsystem can preferably be obtained by the reaction of compounds of formula II with unsubstituted or single or double substituted (i.e., substituted with COOH, COOA, CONH2, CONAAxe2x80x2, CONHA or CN) saturated 5-7 membered heterocyles.
The compounds of Formula II are generally known. To the extent they are not specifically known or described previously, they can be synthesized by known methods. Precursors to the compounds of Formula II can e.g., be synthesized by cyclisation or halogenation according to Med. Chem. 24, 374 (1981). Subsequent reaction with arylalkylamines yield compounds of Formula II.
In particular, the reaction of compounds of Formula II with the NH-containing heterocycle takes place in the presence or in the absence of an inert solvent at temperatures between approximately xe2x88x9220xc2x0 C. and approximately 150xc2x0 C., preferably between 20xc2x0 C. and 100xc2x0 C.
The addition of an acid binding agent, e.g., an alkali or alkaline earth metal hydroxide, carbonate or bicarbonate or of another salt of a weak acid of the alkali or alkaline earth metals, preferably of potassium, sodium or catcium, or the addition of an organic base like triethylamine, dimethylamine, pyridine or quinoline or an excess of the amine component can be enhancing.
As inert solvents the following can be used: hydrocarbons (e.g., hexane, petrolether, benzene, toluene, xylene), chlorinated hydrocarbons (e.g., trichloroethylene, 1,2-dichlorethane, carbontetrachloride, chloroform or dichloromethane), alcohols (e.g., methanol, ethanol, isopropanol, n-propano, n-butanol, tert. Butanol), ethers (e.g., diethylether, disopropylether, tetrahydrofurane (THF) or dioxane), glycolethers (e.g., ethyleneglycolmono methyl or monoethylether (methylglycol or ethylglycol), ethyleneglycoldimethylether (diglyme)), ketones (e.g., acetone or butanone), amides (e.g., acetamide, dimethylacetamide or dimethyl formamide (DMF)), nitrites (e.g., acetonitrile; sulfoxides like dimethysulfoxide (DMSO)), nitro compounds (e.g., nitromethane or nitrobenzene), esters (e.g., ethylacetate), or mixtures of these solvents.
Compounds of Formula III can be obtained from compounds derived from thiophenderivatives and CN-substituted heterocycles by reaction with POCl3 (Eur. J. Med. Chem. 23, (1988).
The reactions of compounds of Formula III and compounds of Formula IV take place under similar conditions regarding reaction time temperature and solvent, as are described for the reactions of compounds of Formula II with NH-containing heterocycles.
To convert a substituent R3 and/or R4 of a compound of Formula I, to another substituent R3 and/or R4 e.g., by reduction of a nitrogroup (e.g., by hydration on Raney-nickel or Pd-charcoal in an inert solvent like methanol or ethanol) to an amino group or by hydrolysis of a cyano group to a carboxylic group.
An acid of formula I with a base can be converted to the corresponding addition salt e.g., by the reaction of equivalent amounts of acid and base in an inert solvent like ethanol and subsequent evaporation. For this reaction bases that yield physiologically non-toxic salts are to be used.
In this way, the acid of Formula I can be transformed with a base (e.g., sodium or potassium hydroxide or carbonate) to the corresponding metal, in particular alkali- or alkaline earth metal or the corresponding ammonium salt.
On the other hand, base of Formula I can be transformed with an acid to the corresponding acid addition salt, e.g., by reaction of equivalent amounts of base and acid in an inert solvent like ethanol and subsequent evaporation. For this reaction acids which give physiologically non-toxic salts can particularly be used, inorganic acids e.g., sulfuric acid, nitric acid, halogenhalides like hydrochloric acid or hydrobromic acid, phosphoric acids like orthophosphoric acid, sulfaminic acid; furthermore organic acids can be used, in particular aliphatic, alicyclic, araliphatic, aromatic or heterocyclic one or multiple base carbonic, sulfonic or sulfuric acids, e.g., formic acid, acetic acid, propionic acid, pivalinic acid, diethylacetic acid, malonic acid, succinic acid, pimelinic acid, fumatic acid, maleinic acid, lactic acid, tartaric acid, 2-hydroxysuccinic acid, citric acid, glucomic acid, ascorbic acid, nicotinic acid, isonicotinic acid, methan- or ethansulfonic acid, ethandisulfonic acid, 2-hydroxyethan-sulfonic acid, benzenesulfonic acid, p-toluene-sulfonic acid, naphthaline-mono- and disulfonic acids, laurylsulfuric acids. Salts with physiologically not acceptable acids, e.g., picrates, can be used for the isolation and/or purification of compounds of Formula I.
In the preceding and the following all temperatures are in xc2x0C. In the following examples the xe2x80x9cusual workupxe2x80x9d means: if necessary, water is added, the pH is, if necessary, adjusted to values between 2 and 10, depending on the constituency of the product, extraction is done with ethylacetate or CH2Cl2, the phases are separated, the organic phase is dried over Na2SO4, evaporated and purified by chromatography on silicagel and/or crystallisation.